Many strains of bacteria produce therapeutically useful substances, such as antibiotics. Some substances useful as the host defense stimulator or immunopotentiator or as the anti-tumor agent are known, but there remains a need for more effective agents useful for therapeutic treatment of various diseases in living animals, including humans.
An object of this invention is to provide new compounds which are useful as the immunopotentiator and/or the anti-tumor agent. A further object of this invention is to provide a process for the fermentative production of these new compounds. Other objects will be clear from the following descriptions.
We have made extensive research in an attempt to produce and obtain new physiologically active compounds. As a result, we have now found that when a new strain of the genus Chromobacterium which was isolated from a soil sample collected at Poropinai on the shore of Lake Shikotsu, Hokkaido, Japan and which was alloted a laboratory designation, BMG361-CF4 strain, is cultivated in a culture medium, there are produced and accumulated in the culture new substances which show activities inhibitory to aminopeptidase B. We have succeeded in isolating these new substances from the culture and purifing them. From the chemical, physical and biological studies of these isolated substances, it has been confirmed that each of these isolated substances is a new compound which is less toxic and which is distinguishable from any of the known compounds. Thus, we have denominated these two new compounds as arphamenine A and arphamenine B, respectively. Arphamenines A and B have the chemical structures and physico-chemical properties as described later.